Transcript Database Principles & Design By Colin Ritchie

Management Information
Systems
By Effy Oz & Andy Jones
Chapter 11: System Planning and
Development
www.cengage.co.uk/oz
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Objectives
• Explain the importance of and steps in IT planning
• Describe the systems development life cycle, which is
the traditional approach to systems development
• Explain the challenges involved in systems
development
• List the advantages and disadvantages of different
system conversion strategies
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Objectives (continued)
• Enumerate and explain the principles of agile
systems development methods
• Explain the concept of systems integration
• Discuss whether IS professionals should be
certified
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Planning Information Systems
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Enterprise ISs gaining in popularity
High risk involved in implementation
Successful integration of system vital
Planning of IS necessary
Align IS and organizational strategies
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Steps in Planning Information Systems
• IS planning includes several key steps
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Create IS mission statement
Articulate vision for IS
Create IS plans
Create operations plan
Create budget
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Steps in Planning Information
Systems (continued)
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Steps in Planning Information
Systems (continued)
• Mission statement: most important overarching goal
of organization
• IS mission statement describes goal of IS
– Should be compatible with organizational
mission statement
• CIO develops strategic plan for implementation
• Goals broken down into objectives
• Objectives broken down to operational details
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Steps in Planning Information
Systems (continued)
• IT planning similar to planning of other resources
• Growing proportion of IT funds spent on software
– More purchasing
– Less developing in-house
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
The Benefits of Standardization in
Planning
• Major goal of planning is standardization
• Many benefits
– Cost savings
• Better bargaining power
• Applies to hardware and software
– Efficient training
• Smaller variety of software
– Efficient support
• More specialization
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
From Planning to Development
• After planning decide how to obtain systems
– Usually software
• Approaches to systems development universal
– Two approaches
• Systems development life cycle (SDLC)
• Nontraditional methods
• Agile methods more efficient
• Prototyping: fast development of application
based on initial requirements
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
The Systems Development Life Cycle
• Large ISs conceived with systems development life
cycle (SDLC)
• SDLC also known as waterfall development
– Consists of sequential phases
• Organizations sometimes take shortcuts
• Four major phases
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Analysis
Design
Implementation
Support
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
The Systems Development Life Cycle
(continued)
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Analysis
• Systems analysis: five-step process
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Investigation
Technical feasibility study
Economic feasibility study
Operational feasibility study
Requirements definition
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Analysis (continued)
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Analysis (continued)
• First step is investigation
– Determine if system necessary
– Small team interviews employees
• Feasibility studies: conducted after IS
warranted
– Technical feasibility
• Determine if components exist
• Adequate hardware
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Analysis (continued)
• Economic feasibility study
– Cost/benefit analysis: spreadsheet showing
costs
• Benefits must outweigh costs
– Return on investment (ROI): most accurate
economic analysis
• Difference between stream of benefits and costs
• Many benefits are intangible
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Analysis (continued)
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Analysis (continued)
• Operational feasibility study
– Determine how new system will be used
– Organizational culture: general tone of
corporate environment
– System compatibility with culture
• Requirements definition
– Project team installed
– System requirements: functions expected from
system
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Design
• Second step in systems development is design
• Systems design: three steps
– Description
– Construction
– Testing
• If purchasing system must determine how to adapt
– Construction requires changing programming code
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Design (continued)
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Design (continued)
• Symbols used to communicate ideas
– Visual information grasped more quickly
• Data flow diagram (DFD): describes flow of
data
– Four symbols
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External entities
Processes
Data stores
Direction of data flow
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Design (continued)
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Design (continued)
• DFD symbols
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External entities are external individuals and groups
Processes are events that change data
Data store is resting data
Data flow is direction that data moves
• Simplicity of DFD is advantage
• DFD suitable for describing non-computer based
IS
• DFD cannot describe system completely
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Design (continued)
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Design (continued)
• Unified modeling language (UML): de facto
standard for diagramming
– Helps developers communicate features
– Provides standard symbols and notations
– Consists of diagrams describing software
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Use case
Class
Interaction
State
Activity
Physical components
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Design (continued)
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Design (continued)
• Construction
– Mostly programming
– Takes months to years
– Testing done on completed modules
• Walk-through logic of program
• Simulation of actual program execution
• System testing
– Test entire integrated system
– Try to “outsmart” system
– Poor testing causes many failures
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Implementation
• Implementation: Two steps
– Conversion
– Training
• Conversion: switching old system to new
– Four basic strategies
• Parallel conversion: old system used with new system
at first
• Phased conversion: break IS into modules and
integrate one at a time
• Cut-over conversion: immediately replace all
• Pilot conversion: introduce in one business unit at a
time
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Implementation (continued)
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Support
• Support: two responsibilities
– Maintenance
• Post-implementation debugging
• Updates
• Adding postponed features
– User help
– Longest phase of system life cycle
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Agile Methods
• Agile methods: alternatives to SDLC
– Treat software development as series of
contacts with users
– Fast development of software
– Improve software after user specifications
received
– Iterative programming
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Agile Methods (continued)
• Popular agile methods
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Extreme programming (XP)
Adaptive software development (ASD)
Lean development (LD)
Rational unified process (RUP)
Feature driven development (FDD)
Dynamic systems development method (DSDM)
Scrum
Crystal
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Agile Methods (continued)
• Agile method risks
– Analysis phase limited or eliminated
• Risk of incompatibilities
– Less documentation
• Difficult modification
• Manifesto for Agile Software Development
prioritizes individuals and interactions over
processes
• Light but sufficient development process
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Agile Methods (continued)
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Agile Methods (continued)
• User involvement encouraged throughout
process
• Test modules immediately after completion
• Communication with users informal
• Two programmers per module
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
When to Use Agile Methods
• Best to use agile method
– When system is small
• Analysis less important
• Small investment of resources
– For unstructured problems
– Users cannot specify all requirements at start
• Unfamiliar with technology
• Difficult to conceptualize
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
When Not to Use Agile Methods
• Do not use agile methods when
– System is large
• System failure entails great financial loss
– Designed to interface with other systems
• SDLC recommended for complex systems
• Documentation is key
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
When Not to Use Agile Methods
(continued)
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Systems Integration
• Systems integration: combine disparate
systems
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Examines needs of entire organization
Allows data to flow between units
Some service companies specialize in this
Integration more challenging than development
Interface legacy systems with new systems
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Systems Integration (continued)
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Systems Integration (continued)
• Systems integrators must be skilled in
hardware and software
• Difficult to overcome incompatibility issues
• Systems integration may span several
organizations
• Integration with telecommunications
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Summary
• IT planning important because of high
investment rate
• Standardization important part of IT planning
• Systems development life cycle (SDLC) has
well-defined phases
• Purpose of systems analysis is to determine
needs the system will satisfy
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Summary (continued)
• Feasibility studies determine if system is possible
and desirable
• System requirements detail features needed
• Developers outline system components
graphically
• Unified Modeling language used to create model
of desired system
• Implementation includes training and conversion
to new system
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning
Summary (continued)
• Support entails maintenance and satisfying
changing needs
• Agile methods are popular alternative to
traditional systems development cycle
• Systems integration more complicated than
systems development
• Great responsibility of IS professionals results
in certification requirements
Use with Management Information Systems 1e
By Effy Oz & Andy Jones ISBN 9781844807581
© 2008 Cengage Learning